Report ASSIGNMENT_TO_CONST.

editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/error/StaticWarningCode.java

Index: editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/error/StaticWarningCode.java
diff --git a/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/error/StaticWarningCode.java b/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/error/StaticWarningCode.java
index 0d0e9c7bad4b631ae23aa2ed06053380e8510537..e4a47a2a10aca5f25b3e83f6f19d6a9530ea5e7d 100644
--- a/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/error/StaticWarningCode.java
+++ b/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/error/StaticWarningCode.java
@@ -66,6 +66,15 @@ public enum StaticWarningCode implements ErrorCode {
    * 5 Variables: Attempting to assign to a final variable elsewhere will cause a NoSuchMethodError
    * to be thrown, because no setter is defined for it. The assignment will also give rise to a
    * static warning for the same reason.
+   * <p>
+   * A constant variable is always implicitly final.
+   */
+  ASSIGNMENT_TO_CONST("Constant variables cannot be assigned a value"),
+
+  /**
+   * 5 Variables: Attempting to assign to a final variable elsewhere will cause a NoSuchMethodError
+   * to be thrown, because no setter is defined for it. The assignment will also give rise to a
+   * static warning for the same reason.
    */
   ASSIGNMENT_TO_FINAL("Final variables cannot be assigned a value"),